1. Field of the Invention
The present invention relates to a one-way clutch assembly which is used, for example, in a starter of a motorcycle or the like.
2. Related Background Art
In the oneway clutch assembly, the constituent members thereof except an outer race, an inner race and a C-shaped retaining ring (hereinafter called the main body unit of the oneway clutch) are rotated slowly between the outer and inner races depending on increase, decrease, or the like, of vibrations or the number of rotations of the engine. This rotation is required for preventing a local abrasion of the outer race or the inner race, and the speed of this rotation is adjusted by an elastic ring or the like provided on a side plate or the like. The technologies therefor are disclosed, for example, in Japanese Utility Model Application Laid-Open Nos. 63-94330, 63-139334 and 4-32335.
For example, in Japanese Utility Model Application Laid-Open No. 63-94330, the oneway clutch is provided with a plurality of sprags which are annularly interposed between the inner race and the outer race, a garter spring for biasing these sprags in the direction of engagement between the inner and outer races, an annular wire retainer alternately having axial parts and circumferential parts for retaining the respective sprags, and an annular side plate interposed between an end surface of the sprag and the retainer to be slidably retained between the inner and outer races.
A window portion is provided on the outer peripheral part of this annular side plate, and an engagement projection of a frictional engagement ring (C-shaped retaining ring) is inserted in this window portion to be engaged therewith. This frictional engagement ring is arranged to be expanded and elastically contacted with the inner peripheral surface of the outer ring.
With this arrangement, at the time of non-engagement of the sprags, that is, at the time of idling rotation of the outer race or the inner race, the engagement projection of the frictional engagement ring which is inserted into the window portion of the annular side plate and expanded to be elastically contacted with the inner peripheral surface of the outer ring rotates the annular side plate to follow the idling rotation of the outer ring. This rotation of the annular side plate causes rotation of a group including the retainer and the sprags (the main body unit of the oneway clutch) in a body.
As a result, though rotating substantially together or in a body with the idling rotation of the outer race, the main body unit of the oneway clutch is rotated gradually around the outer race relatively thereto, depending on an increase or a decrease in the vibrations or the number of rotations of the engine. Thereby, it is rendered possible to prevent local abrasion of the outer race or the inner race, and at the same time, to securely shift an idle rotation of the oneway clutch to a meshing operation without sliding.
In Japanese Utility Model Application Laid-Open No. 63-94330, a window portion is provided on the outer peripheral part of the annular side plate, and an engagement projection of a frictional engagement ring (C-shaped retaining ring) is inserted in this window portion to be engaged therewith.
However, the annular side plate has a flange which is projected in the axial direction on the outer peripheral end thereof and the above-described window portion is provided on this flange, so that the width dimension in the axial direction thereof is disadvantageously increased by the projected portion of the flange.
There is also a demand for further increase of a frictional torque between the main body unit of the oneway clutch and the outer race or the like at the idling rotation time of the outer race or the like.